Chang et al. U.S. Pat. No. 4,788,420, entitled "System and Method for Reading Data Record Stripes on Data Cards," discloses one form of prior art point of sale terminal which incorporates a card reader assembly. The Chang et al. terminal utilizes a card guide which is integrally molded into the terminal case. A metal wear strip is molded into the bottom of the card guide slot to provide a surface which has better wear characteristics than the plastic material from which the terminal housing is formed in an injection molding process. In other prior art terminals generally following the same design approach, a separate metal wear strip is fastened to the terminal housing to form the bottom wall of a card guide slot and thereby provide longer wear characteristics. Other terminals use a metal strip to form both one side wall and the bottom wall of the card guide.
Kobayashi et al. U.S. Pat. No. 4,304,992, entitled "Magnetic Card Reader" discloses (FIGS. 4-6) a card reader in the form of a separate module with a housing that defines the card slot and encloses both the read head and decoder electronics for processing signals from the read head as a card is wiped through the slot. The card reader module is designed to be mounted to a point of sale terminal to provide a card reading function.
It is also known in the prior art to provide complete card reader subassemblies (i.e. with read head and decoder electronics together in a separate housing) that are designed to be physically integrated into the case of a point of sale terminal. For example, Tokin Corporation sells a card reader subassembly in which a read head mounting frame snaps onto a card guide element. However, the mounting frame has a single mounting position and utilizes a combination of a hanging bracket arrangement on a top portion and a snap fastening arrangement on a bottom portion. The accuracy of the mounting position of the mounting frame depends on accuracy of forming the elements of the hanging bracket, including hanger tabs provided on top of a frame support structure attached to the card guide element, and cooperative hanger slots formed on a top portion of the mounting frame itself. The snap fastening arrangement comprises a pair of snap tabs formed on a bottom section of the card guide element cooperating with snap tab receiving slots in a bottom wall surface on the mounting frame.
The snap tabs are relatively weak and fragile and susceptible to being broken off in rough handling of the unit prior to assembly of the two pieces.
The read head frame of the Tokin unit carries a magstripe read head which is mounted in a separate bracket through which a thin pin-type spring extends. Two mounting groove arrangements on the read head frame define two optional mounting support positions for the spring and thus define two mounting positions for the read head relative to the card guide for reading different tracks on the magnetic stripe.
Assembly of this unit involves mounting the read head into its metal bracket. Then the spring pin is placed through the holes in the metal bracket and this assembly is placed on the read head mounting frame in one of the two mounting positions. Then this assembly of head and mounting frame is mounted onto the card guide element by hanging the frame on the hanger portion and then snapping the frame onto the snap tabs. The separate read head bracket and spring add both parts and assembly labor to the overall cost of the unit.